LMMS didn't compile successfully if individual paths to headers of
each Qt module were not added to the list of include directories to be
searched by the pre-processor. However it has to work this way,
therefore I changed lines like
#include <QGraphicsScene>
to
#include <QtGui/QGraphicsScene>
Please care in the future!
Signed-off-by: Tobias Doerffel <tobias.doerffel@gmail.com>